Solved
Do replication agents use the Sling Job Thread Pool?
Do replication agents use the Sling Job Thread Pool (org.apache.sling.event.impl.EventingThreadPool)? If not, is there another thread pool used for replication?
The thread pool is managed by sling eventing. The settings for how events are processed as sling job threads are configured as an instance of org.apache.sling.event.jobs.QueueConfiguration: